Reinforcement fabrics made from fibrous materials formed into woven, knitted and non-woven material, are well known in the art. Yarns of glass, carbon and aramid are typically formed into fabrics, and a plurality of layers of fabric are stacked and cut into dry fabric kits or performs. The performs are then infused or impregnated with a resin binder and cured to form a rigid composite.
Typically a glass reinforced fibrous mat is preformed and then placed in a mold for molding into a fiber-reinforced article. Glass fiber-reinforcement mats are used in situations where a desired strength is necessary, such as in truck fenders, auto chassis or bus components and the like. For example, layers of the continuous strand mat and layers of unidirectional or multidirectional reinforcement material are fabricated separately. These layers are individually placed in a set of preformed screens, which generally consist of an upper screen and a lower screen. The upper and lower screens are moved together in order to conform the layers to the shape of the preformed screens. The layers are thus shaped into what is known as a preform. The preform is then placed in a mold and injected with a suitable resinous material to make the fiber reinforced article.
U.S. patent application Ser. No. 10/674,987, filed on Sep. 30, 2003, (OC Case No. 25253) now U.S. Pat. No. 7,168,272, issued on Jan. 30, 2007, owned by the assignee of the present invention, discloses a crimp-free infusible reinforcement fabric. The unidirectional fabric has small size tows spaced between large size tows. The “channels” that are formed from the small tows between the larger tows permit faster resin infusion and increased productivity.
The present invention relates to an improved infusion fabric that better optimizes knitting, preforming, conformability to tooling, resin infusion rate, consolidation thickness, surface aesthetics, and composite structural performance in a range of closed molding processes including VIP, RTM and RTM Lite or VARTM processes. This represents the full range of composite closed molding processes used by marine, wind, construction, transportation and industrial customers. In addition, the present invention relates to a novel continuous filament mat and binder useful in making that improved infusion fabric mat.